Since LCD panels have the advantages of being slim and low power consumption, they are commonly used in many portable appliances such as word processors, personal computers and televisions, as well as the viewfinders and monitors of video cameras. In recent years, there has been adopted a reflective-type LCD panel using external light as a light source in place of backlight.
However, in a display panel using a liquid crystal layer as a light modulation layer, there arises a problem that flickers are generated when a frame rate (i.e., frames number to be rewritten on a display screen per a second) is lowered. On the other hand, when a frame rate is made higher to suppress the occurrence of flickers, the circuit scale of the display unit is increased to be a problem.
In a simple matrix type LCD panel, an amplitude of a common selection signal for selecting a common driver IC is much larger than an amplitude of a segment data signal for a segment driver IC. Therefore, when a common driver IC and a segment driver IC are to be assembled as one semiconductor chip, it is necessary that a tolerance voltage of the semiconductor chip must be matched with an amplitude of the selection signal. Accordingly, a high tolerance voltage processing is required as an IC process, and it was difficult in cost to combine a common driver and a segment driver as one semiconductor chip. This is because it was difficult to achieve a display panel having a construction of three free sides having no driver IC and only one side thereof formed with driver IC chip thereon.
Recently, information terminals of mobile or portable telephones are progressing, and there is a demand for realizing a high quality or good contrast display of a moving picture even in a mobile telephone. In order to achieve a high contrast display of a moving picture, the frame rate must be made high. The frame rate is proportional to a power consumption, and the power consumption is increased when the frame rate is made high. However, suppression of power consumption is essentially required in a mobile telephone, and therefore there is a demand for realizing both a good display of a moving picture and a low power consumption compatibly.
In a mobile telephone network, there is adopted a charge system in which a charge for usage is decided in accordance with a data transmission time or data transmission amount. Namely, it is required that image data should be transferred in a short time with suppressing the transmission data amount as small as possible. Moreover, when the image data amount is increased, the circuit operation of a mobile telephone is complicated and the power consumption is increased to be problematic.
An essential object of the present invention is to provide a display device and driving system, construction and method solving these shortcomings.